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  • 201. Kis, S. A.
    et al.
    Valastyán, I.
    Hegyesi, Gy.
    Imrek, J.
    Kalinka, G.
    Molnár, J.
    Novák, D.
    Végh, J.
    Balkay, L.
    Emri, M.
    Molnár, G.
    Bagaméry, I.
    Bükki, T.
    Rózsa, S.
    Szabó, Zs.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Trón, L.
    Performance Characteristics of a miniPET Scanner Dedicated to Small Animal Imaging2005In: 2005 IEEE Nuclear Science Symposium Conference Record, 2005, 1645-1648 p.Conference paper (Refereed)
    Abstract [en]

    An easy to scale up modular PET scanner was developed for imaging small animals. Energy resolution, spatial resolution and count rate performance were determined as system parameters. The configuration provided an average energy resolution of 19.6 % and the image resolution ranges was 1.5 to 2.3 mm in radial direction. The sensitivity of the miniPET was 1.08 cps/kBq as determined using a point source. In addition, results of rat brain scan performed with FDG are given to characterize imaging capability of the system. The displayed data document that the miniPET scanner supports good quality brain imaging of small animals.

  • 202.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    A Parametric Study of Energy Absorbing Foams for Head Injury Prevention2007In: The 20th ESV Conference Proceedings, 2007Conference paper (Refereed)
    Abstract [en]

    This paper describes a parametric study of foammaterial properties for interior car surfaces usingfinite element calculations. Two different headmodels were used for the impact simulations, aHybrid III dummy head and a biomechanical headmodel. The objective was to study the head injurycriterion (dummy) (HIC(d)), the angular velocity, theresultant acceleration and, for the human headmodels, the strain in the brain tissue and the stress inthe skull for a variation in foam material propertiessuch as stiffness, plateau stress and energyabsorption. The analysis gave at hand that the bestchoice of material properties with respect to impactusing the Hybrid III head model reached differentresults compared to an impact with the biomechanicalhead model. For a purely perpendicular impact, theHIC(d) for the head model managed to predict thestrain level in the brain quite well. Even though theHIC reached acceptable levels for both aperpendicular and oblique impact towards a 31 kg/m3EPP padding, the maximum strain in the human headmodel for an oblique impact was almost twicesuggested allowable levels. The difference in thestrain in the brain between an oblique andperpendicular impact when impacted with sameinitial velocity towards the same padding was notpredicted by the HIC(d).

  • 203.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Biomechanics and thresholds for MTBI in humans2008In: IBIA 2008: MTBI Pre-Congress Symposium, 2008Conference paper (Refereed)
  • 204.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Biomechanics of sports head injury and helmet design2011Conference paper (Other academic)
  • 205.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Biomechanics of traumatic brain injuries and head injury criteria2011Conference paper (Refereed)
  • 206.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Cycle helmets2011In: IOC World Conference on Prevention of Injury & Illness in Sports: Sports helmets now and in the future, 2011Conference paper (Other academic)
  • 207.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Förståelse för biomekaniken bakom traumatiska skallskador genom finit element modellering av det mänskliga huvudet2007Conference paper (Other academic)
  • 208.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Förståelsen för biomekaniken bakom traumatiska skallskador genom finit elementmodelleing av det mänskliga huvudet2005Conference paper (Other academic)
  • 209.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Influence of Anatomical Features and Modelling Strategies in Traumatic Brain Injury Prediction2010Conference paper (Other academic)
  • 210.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Influence of Anatomical Features and Modelling Strategies in Traumatic Brain Injury Prediction2010Conference paper (Other academic)
  • 211.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Influence of direction and duration of impacts to the human head evaluated using the finite element method.2005In: International Research Council on the Biomechanics of Impact - 2005 International IRCOBI Conference on the Biomechanics of Impact, Proceedings:  , 2005, 41-57 p.Conference paper (Refereed)
    Abstract [en]

    The objective of the present study was to analyze the effect of different loaddirectionsanddurationsfollowingimpactusing a detailedfiniteelementmodel of thehumanhead. It was found that theinfluenceofimpactdirectionhad a substantial effect on the intracranial response. When evaluating the global kinematic injury measures for the rotational pulses, the change in angular velocity corresponded best with the intracranial strains found in the FE model. For the translational impulse, on the other hand, the HIC and the HIP showed the best correlation with the strain levels found in the model.

  • 212.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Mathematical models used in TBI2010Conference paper (Other academic)
    Abstract [en]

    In Sweden, head injuries causes about 78% of the deaths in motor vehicle accidents. The total annual rate of head injuries in Sweden over the last 14 years is also relatively constant. Thus, in spite of several national preventive strategies, there has not been an important impact on the total burden of head injury. Neurotrauma is the physical damage that results when the human skull and brain are suddenly subjected to intolerable levels of energy that is usually transmitted mechanically. Most of the research in the injury prevention area was initiated by the military aircraft industry in the sixties and seventies. Today the research is to a greater extent sponsored by the car manufacturing industry, partly as a result of the demands from the customers and the media. However, there is a long way to go before a complete understanding of the pathophysiological events following an accident is reached. This paper primarily focuses on summarizing current efforts, and to outline future strategies in human head injury modeling. Although the finite element (FE) modeling of the human head has been advancing over the past decades, it is still far from being able to explain all brain injury mechanisms and predict all types of impact injuries. However, using proper material characterization, correct boundary conditions and detailed geometric representation, a finite element model of the human head can provide us a powerful tool. A detailed and parameterized FE model of the adult human head is presented. It includes the scalp, skull, brain, meninges, cerebrospinal fluid (CSF), and eleven pairs of bridging veins. Separate representations of gray and white matter, and inclusion of the ventricles were also implemented. Non-linear and viscoelastic models are derived for the central nervous system (CNS) and meninges and the importance for injury prediction is outlined. The fluids were modelled using an Eulerian FE formulation, and constrains between fluids and solids were defined. Proposed injury measures for the CNS are also evaluated. Application of the FE head model to reconstructions of real head injury cases will also be discussed.

  • 213.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Ny diagnostisk bildmetod för analys av händelseförloppet2007Conference paper (Other academic)
  • 214.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Parametric studies of the ballistic helmet design2007Conference paper (Refereed)
  • 215.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    The biomechanics of ‘real’ head protection: New thoughts on preventing TBI2008Conference paper (Other academic)
  • 216.
    Kleiven, Svein
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Johnson, Ho
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Sandler, Håkan
    Rättsmedicinalverket, Uppsala universitet.
    Finite Element Methodology and infant skull fracture: accident or abuse ?2009Conference paper (Other academic)
  • 217.
    Kleiven, Svein
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Juntikka, Rickard
    Optimization of Single Skin Surfaces for Head Injury Prevention – A Comparison of Optima Calculated for Global versus Local Injury Thresholds.2003Conference paper (Refereed)
  • 218.
    Kleiven, Svein
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    CONSEQUENCES OF BRAIN SIZE FOLLOWING IMPACT IN PREDICTION OF SUBDURAL HEMATOMA EVALUATED WITH NUMERICAL TECHNIQUES2001In: IRCOBI (International Research Council on the Biokinetics of Impacts), 2001, 161-172 p.Conference paper (Refereed)
  • 219.
    Kleiven, Svein
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Influence of Direction and Duration of Impact to the Human Head2002Conference paper (Refereed)
  • 220.
    Klintström, Benjamin
    et al.
    KTH, School of Technology and Health (STH).
    Klintström, E.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Feature space clustering for trabecular bone segmentation2017In: 20th Scandinavian Conference on Image Analysis, SCIA 2017, Springer, 2017, Vol. 10270, 65-75 p.Conference paper (Refereed)
    Abstract [en]

    Trabecular bone structure has been shown to impact bone strength and fracture risk. In vitro, this structure can be measured by micro-computed tomography (micro-CT). For clinical use, it would be valuable if multi-slice computed tomography (MSCT) could be used to analyse trabecular bone structure. One important step in the analysis is image volume segmentation. Previous segmentation techniques have either been computer resource intensive or produced sub-optimal results when used on MSCT data. This paper proposes a new segmentation method that tries to balance good results against computational complexity. Material. Fourteen human radius specimens where scanned with MSCT and segmented using the proposed method as well as two segmentation methods previously used to segment trabecular bone (Otsu and Automated Region Growing (ARG)). The proposed method (named FCH) uses a combination of feature space clustering, edge detection and hysteresis thresholding. For evaluation, we computed correlations with the reference method micro-CT for 7 structure parameters and measured segmentation time. Results. Correlations with micro-CT were highest for FCH in 3 cases, highest for ARG in 3 cases, and in general lower for Otsu. Both FCH and ARG had correlations higher than 0.80 for all parameters, except for trabecular thickness and trabecular termini. FCH was 60 times slower than Otsu, but 5 times faster than ARG. Discussion. The high correlations with micro-CT suggest that with a suitable segmentation method it might be possible to analyse trabecular bone structure using MSCT-machines. The proposed segmentation method may represent a useful balance between speed and accuracy.

  • 221.
    Koeck, Philip J. B.
    et al.
    Karolinska Institutet.
    Purhonen, P.
    Alvang, R.
    Grundberg, B.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    3D-correlation-averaging for membrane-protein-crystals2008In: EMC 2008 14th European Microscopy Congress, 2008, 55-56 p.Conference paper (Refereed)
    Abstract [en]

    Few 2-dimensional protein crystals can be used to determine high-resolution structures, whereas most electron crystallography projects remain at a resolution around 10 Ångström. This might be partly due to lack of flatness of many two-dimensional crystals [1]. We have investigated this problem and suggest single particle projection matching (3D-correlation averaging) of locally averaged unit cells to improve the quality of three-dimensional maps. Theoretical considerations and tests on simulated data demonstrate the feasibility of this refinement method [2].

  • 222.
    Kornevs, Maksims
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Logistics and Informatics in Health Care.
    Kringos, Nicole
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges. KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    Meijer, Sebastiaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science. KTH, School of Technology and Health (STH), Health Systems Engineering.
    Using Q Methodology for Developing a System Dynamics Model: A Case Study of Modelling Perspectives on Road Procurement in Sweden2016Conference paper (Refereed)
    Abstract [en]

    The importance of strategic and dynamic behaviour in real-world systems is paramount, especially when we consider the large technical infrastructures that make society work. Modelling social aspects are complicated because they are usually not well defined and can highly depend on individuals. This paper proposes and describes a framework on how to combine system dynamics and Q methodology to better understand complex systems. The proposed framework is the tool to work with systems where connections can be explained only by subjective opinions, and it gives opportunities to simulate sociotechnical systems, where social behaviour cannot be described with observation data.

  • 223.
    Kornevs, Maksims
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Logistics and Informatics in Health Care.
    Kringos, Niki
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Meijer, Sebastiaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science. KTH, School of Technology and Health (STH), Health Systems Engineering.
    Perspectives of Stakeholders on Road Procurements: In search of Procurement Aspects using Q Methodology2016Conference paper (Refereed)
    Abstract [en]

    Nowadays much emphasis is given to innovative procurement in the road construction sector. However, typical discussions about it do not focus on all the stakeholders involved in the process and all aspects. However, one cannot forget that procurement is a complex system, and everyone’s perspective is important for success. This paper looks at the worldviews of stakeholders in the road construction industry. The Q methodology is used to analyse the subjectivity of the worldviews. As a result, it is possible to look deeper into the perspectives and to see what each stakeholder sees as most important, and also to compare different worldviews among stakeholders.

  • 224.
    Kothapalli, Satya V. V. N.
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    Dynamic and Structural Behavior of Magnetic PVA-Shelled Microbubbles: Acoustic Characterization2013In: IEEE International Ultrasonics Symposium / [ed] Dr. AHMAD SAFARI, 2013, 1509-1512 p.Conference paper (Refereed)
    Abstract [en]

    Combination of superparamagnetic iron oxide nanoparticles (SPOINs) and the polymer-shelled microbubble (MB) are proposed to be a contrast agent for both magnetic resonance and ultrasound imaging. The introduction of nanoparticles into MBs changes the material properties of encapsulating shell, which further influences on MBs performance as an ultrasound contrast agent. Magnetic MBs were prepared in two following strategies: 1. SPIONs were attached on the surface of MBs (Type A) and 2. SPIONs were physically entrapped in the MBs shell during the initial formation of PVA shell (Type B). A modified Church model was used to fit the attenuation coefficient spectra acquired experimentally. This allowed to recalculate the viscoelastic properties, i.e. storage and loss modulus, and dynamical properties, i.e. resonance frequency and damping coefficient of two types of magnetic MBs. The cross-correlation analysis of the time-domain response from the MBs suspension was used to identify pressure threshold at which MBs shell fractures. Higher values of both viscoelastic and dynamic characteristic were identified for MBs Type B. The estimated total damping ratio above 1 suggested that the MBs Type B behave as an overdamped harmonic oscillator whereas MBs Type A with total damping ratio below 1 possess underdamped harmonic oscillator nature. The predicted resonance frequencies are approximately 13 and 27 MHz for MBs Type A and B respectively. Moreover, the fracture pressure threshold measurements revealed that, higher peak negative pressure is required to fracture MBs Type B than Type A. When the driving pulse consists of 12 cycles, pressure threshold was 1.1 MPa and 1.3 MPa for MBs Type A and B respectively. In conclusion, MBs with nanoparticles loaded on the surface (Type A) appear to be more acoustically active, demonstrate lower resonance frequency, damping and fracture pressure threshold, than MBs with nanoparticles incorporated in the shell (Type B).

  • 225.
    Kothapalli, Veera Venkata Satya Naray
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering.
    Optimization of driving pulse envelopes in detection of harmonic response from lipid-shelled ultrasound contrast agent2012In: 19th International Congress on Sound and Vibration 2012, ICSV 2012: Volume 3, 2012, 2012, 1882-1889 p.Conference paper (Refereed)
    Abstract [en]

    The assessment of the harmonic response is commonly used in analysis of the signals from ultrasound contrast agents (UCAs). Theoretical and experimental studies report that acoustic behavior of UCAs strongly depends on insonation pressure. Other system parameters, such as the number of cycles, driving and repetition frequency and the pulse shape are equally important. The major focus of this work is to investigate the effect of the shape of driving pulse envelopes on detection of second- (2f), super- (3f, 4f, 5f), sub- (f/2), and ultra-harmonics (3f/2). In this paper, numerical simulations on thin-shelled lipidic UCA have been performed. The simulation results indicate that, high sidelobe suppression envelopes (e.g. 4-term Blackman-Harris), manage to detect second and third harmonic with harmonic-to-fundamental ratio (HFR) of 32 and 69 dB, respectively, at low acoustic pressure of 5 kPa. However, conventional low sidelobe suppression envelopes (e.g. rectangular, cos-tapered, Hanning, Gaussian) fail to identify the harmonic response. Yet the increase of the insonation pressure to 200 kPa leads to increase of the broadband noise. This negatively effects the frequency resolution when high suppression sidelobe envelopes are applied to the driving pulse. As a result, the application of conventional envelopes in harmonic response detection at intermediate acoustic pressure, is recommended. It is also worth mentioning, that at high isonation pressure of 0.9 MPa, cos-tapered envelope, having a side lobe fall-off equal to 18 dB/octave, is able to identify the sub- and ultra-harmonics. In conclusion our study demonstrates that the driving pulse envelope should be selected according to the incident pressure for the complete exploitation of the unique nonlinear signature from UCA. A compromise could be found with the application of adjustable Kaiser-Bessel envelope where by varying the β parameter from 0 to 10 one goes from low to high sidelobe suppression envelope.

  • 226.
    Kothapalli, Veera Venkata Satya Naray
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Paradossi, Gaio
    Diapartimento di Chimica, Università di Roma Tor Vergata.
    Coded Excitation Technique in Detection of Polymeric-Shelled Ultrasound contrast Agents: in Vitro Study2011In: 8th International Conference on Nanosciences & Nanotechnologies (NN11) 12-15 July 2011, Thessaloniki, Greece.: Workshop: NANOMEDICINE, 2011Conference paper (Refereed)
    Abstract [en]

    A novel ultrasound contrast agent (UCA) based on air-filled polymer-shelled microbubbles, is prepared within 3MiCRON project for multimodality approach covering ultrasound, MRI and SPECT investigation. These bubbles have thick, about 30% of the radius, shell providing greater stability and longer half life in a pulmonary circulation compare to commercially available phospholipid UCAs. In addition, extensive storage capacity and possibility to incorporate drugs or pharmacological relevant materials are inherited to these bubbles. 

    Understanding the behavior of the UCA under ultrasound exposure is paramount to the proper and total exploitation of all unique features that these gas-filled microdevice offers. Even though, thickness of the polymeric shell is considerably higher than of commercial UCAs, the enhancement of backscattered power of about 25 dB produced from suspension insonified at low pressure (100 kPa) was observed. It should be noted that thick polymer shell could still be disrupted by high pressure (1 MPa) ultrasonic pulse. Nevertheless, diagnostic imaging typically utilizes the intermediate pressure level, where nonlinear oscillation of the microbubbles give rise to harmonic component in the received echo. It was observed that at pressure level of 400 kPa, Pulse Inversion (PI) technique fail to distinguish between the regions filled with polymer UCA and surrounding ultrasound phantom, mimicking liver tissue. 

    In this paper, a coded excitation technique is proposed to characterize the non-linear properties of the polymer-shelled microbubbles in vitro at intermediate pressure. For a decade ago, coded excitation technique has been adopted into the ultrasound scanners in order to increase the signal-to-noise ratio (SNR) and penetration depth, while matching filters compensates the decrease in axial resolution. In the proposed method, a time domain signal is modulated by a several window functions (e.g. Blackman-Harries, Hanning, Hamming, and Kaiser-Bessel) with or without linear chirp pulses constructed for experiments in vitro. 

    Our preliminary results suggest that coded excitation technique offers an increase of approximately 15dB in contrast-to-tissue ration (CTR) compared to the result achieved from a commercially available Pulse Inversion technique. 

    In conclusion, proposed polymer-shelled microbubbles provide a viable system to be used among the next generation of UCAs, and in combination with improved signal handling is superior not only in image enhancement relevant to diagnostics but also in localized and specific drug delivery for non-invasive therapy. 

  • 227.
    Kothapalli, Veeravenkata Satya
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    Diapartimento di Chimica, Università di Roma Tor Vergata.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet (KI), CLINTEC – Division of Medical Imaging and Technology.
    Dynamic and Structural behavior of Magnetized PVA-shelled Microbubbles: Acoustic Characterization2013Conference paper (Refereed)
  • 228. Kremer, F.
    et al.
    Rabayah, M.
    Choi, H.F.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    D'hooge, Jan
    Spatial compounding for 2D strain estimation in the mouse heart: a pilot study2010Conference paper (Refereed)
    Abstract [en]

    Estimating cardiac strain in the mouse in the lateral direction usingspeckle tracking with adapted clinical equipment was shown to be challenging dueto the fast heart rate and the large speckle size relative to the wallthickness. Compounding axial motion estimates acquired from different insonationangles can potentially improve lateral strain estimates. Therefore, the aim ofthis study was to test the feasibility of this methodology in the murine heartbased on simulated data sets. A 3D kinematic model of a murine left ventriclewas simulated and filled randomly with scatterers. Ultrasound short-axis images(10mm 6mm) were obtained by assuming a linear array transducer. Beam steeringwas simulated at 3 different angles (22, 0, 22). Axial motion was estimated ineach data set by 1D cross-correlation. A dynamic programming approach wasintegrated in the motion estimation algorithm to avoid discontinuities. Axialcomponents were combined to reconstruct the in-plane motion vector. The 2Ddisplacement fields were subsequently accumulated over the whole cycle. Theprocedure was repeated for 10 different distributions of scatterers to acquire10 different RF data sets (5 for parameter tuning and 5 for comparing themethods). Radial and circumferential RMS strain errors calculated from theaccumulated motion fields were compared with those obtained with 2D speckletracking. Spatial compounding yielded significantly better radial (RMSE: 0.07370.0078 vs. 0.112 0.0094) as well as circumferential strain (RMSE: 0.102 0.0097vs. 0.281 0.054).

  • 229.
    Kölegård, Roger
    et al.
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Betydelse av in vivo styvhet hos perifera blodkärl ur ett flygmedicinskt perspektiv2011Conference paper (Refereed)
  • 230.
    Kölegård, Roger
    et al.
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Sundblad, Patrik
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Grönkvist, Mikael
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Är det möjligt att uppskatta Gz-tolerans medelst ortostatisk prov?2015Conference paper (Refereed)
  • 231.
    Larsson, Daniel
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Roy, J.
    Gasser, T. Christian
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Urban, M. W.
    Colarieti-Tosti, Massimiliano
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    An ex-vivo setup for characterization of atherosclerotic plaque using shear wave elastography and micro-computed tomography2016In: IEEE International Ultrasonics Symposium, IUS, IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    Quantification of the mechanical properties of atherosclerotic plaque has shown to be important in assessing carotid artery plaque vulnerability. For such, shear wave elastography (SWE) has been applied on both in-vitro and in-vivo setups. The aim of this study was to build an ex-vivo setup for combined evaluation of plaque characteristics using SWE and micro-computed tomography (μCT). As a proof-of-concept of the constructed experimental setup, a single human carotid plaque specimen was extracted during carotid endarterectomy. The plaque was imaged in the μCT system, and subsequently imaged using SWE. For the SWE measurement, group and phase velocity was extracted from the obtained in-phase/quadrature data, with its spatial distribution being compared to anatomical features visible in the μCT images. The results indicated wave velocity changes at boundaries identified in the μCT, with group velocity data slightly increasing when entering a calcified nodule. Additionally, μCT images seemed to provide good contrast between several plaque constituens using the defined imaging settings. Overall, the study represents a proof-of-concept for detailed ex-vivo plaque analysis using combined SWE and μCT, with obtained wave speed and shear modulus values falling within observed values for atherosclerotic plaque tissue. With an experimental setup defined, future studies on carotid plaque behaviour both in SWE and μCT is enabled, where a large-scale plaque study could be performed to investigate the ability of SWE to differentiate between different plaque types. © 2016 IEEE.

  • 232.
    Larsson, David
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Spuhler, Jeannette H.
    KTH, School of Computer Science and Communication (CSC), High Performance Computing and Visualization (HPCViz).
    Nordenfur, Tim
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Hoffman, Johan
    KTH, School of Computer Science and Communication (CSC), High Performance Computing and Visualization (HPCViz).
    Colarieti-Tosti, Massimiliano
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Gao, Hang
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Patient-specific flow simulation of the left ventricle from 4D echocardiography - feasibility and robustness evaluation2015In: 2015 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    In recent years, computational fluid dynamics (CFD) simulations on in-silico models of the heart have provided a valuable insight into cardiac hemodynamic behaviour. However, so far most models have been either based on simplified geometries or on imaging acquisitions with relatively low temporal resolution. It has been suggested that models based entirely on subject-specific ultrasonic images should be used to capture transient flow changes. Therefore, the aim of this study is to present a pathway from routine 4D echocardiography to a patient-specific flow simulation of the left ventricle (LV), evaluating the model robustness and clinical feasibility. The created pathway consisted of initial LV segmentation and mitral/aortic valve positioning, being subsequently used as input for the CFD simulations (based on solving the Navier-Stokes equation using an Arbitrary Lagrangian-Eulerian approach). The output consisted of 4D blood flow velocities and relative pressures in the entire LV. On five subjects, the model robustness was evaluated with regards to variations in singular boundary conditions. The clinical feasibility of the output was compared to clinical PW Doppler measurements and, as a proof-of-concept, synthetic contrast enhanced ultrasound images were simulated on the flow field using the COLE-method. Results indicated a relatively robust model, with variations in regional flow of approximately 5.1/6.2% and 9.7/7.0% for healthy and pathological subject respectively (end diastole/end systole). Furthermore, showing similar behaviour to clinical Doppler measurements the technique serves as a promising tool for future clinical investigations. Additionally, the ability of simulating synthetic ultrasound images further underlines the applicability of the pathway, being potentially useful in studies on improved echocardiographic image analysis.

  • 233.
    Larsson, David
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Spuhler, Jeannette H.
    Petersson, Sven
    Nordenfur, Tim
    Hoffman, Johan
    KTH, School of Computer Science and Communication (CSC), High Performance Computing and Visualization (HPCViz).
    Colarieti-Tosti, Massimiliano
    Winter, Reidar
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Multimodal validation of patient-specific intraventricular flow simulations from 4D echocardiography2016In: 2016 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    The combination of refined medical imaging techniques and computational fluid dynamics (CFD) models has enabled the study of complex flow behavior on a highly regional level. Recently, we have developed a platform for patient-specific CFD modelling of blood flow in the left ventricle (LV), with input data and required boundary conditions acquired from 4D echocardiography. The platform robustness has been evaluated with respect to input variable variations, but for any clinical implementation model flow validation is essential. Therefore, the aim of this study is to evaluate the accuracy of the patient-specific CFD model against multimodal image-based flow measurements. For the validation, 4D echocardiography was acquired from two healthy subjects, from which LV velocity fields were simulated. In-vivo flows from the same two subjects were then acquired by pulsed wave (PW) Doppler imaging over both LV-valves, and by cine phase-contract magnetic resonance imaging (PC-MRI) at eight defined anatomical planes in the LV. By fusing PC-MRI and the ultrasound acquisitions using a three-chamber alignment algorithm, simulated and measured flows were quantitatively compared. General flow pattern correspondence was observed, with a mean error of 1.4 cm/s and root mean square deviation of 5.7 cm/s for all measured PC-MRI LV-planes. For the PW-Doppler comparison, a mean error of 3.6 cm/s was reported. Overall, the following work represents a validation of the proposed patient-specific CFD platform, and the agreement with clinical data highlight the potential for future clinical use of the models.

  • 234.
    Larsson, David
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Insitutet, Sweden.
    Spühler, Jeannette
    KTH, School of Computer Science and Communication (CSC), Computational Science and Technology (CST).
    Günyeli, E.
    Weinkauf, Tino
    KTH, School of Computer Science and Communication (CSC), Computational Science and Technology (CST).
    Hoffman, Johan
    KTH, School of Computer Science and Communication (CSC), Computational Science and Technology (CST).
    Colarieti-Tosti, Massimiliano
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet, Sweden.
    Winter, R.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet, Sweden.
    Estimation of left ventricular blood flow parameters: Clinical application of patient-specific CFD simulations from 4D echocardiography2017In: Medical Imaging 2017: Ultrasonic Imaging and Tomography, SPIE - International Society for Optical Engineering, 2017, Vol. 10139, 101390LConference paper (Refereed)
    Abstract [en]

    Echocardiography is the most commonly used image modality in cardiology, assessing several aspects of cardiac viability. The importance of cardiac hemodynamics and 4D blood flow motion has recently been highlighted, however such assessment is still difficult using routine echo-imaging. Instead, combining imaging with computational fluid dynamics (CFD)-simulations has proven valuable, but only a few models have been applied clinically. In the following, patient-specific CFD-simulations from transthoracic dobutamin stress echocardiography have been used to analyze the left ventricular 4D blood flow in three subjects: two with normal and one with reduced left ventricular function. At each stress level, 4D-images were acquired using a GE Vivid E9 (4VD, 1.7MHz/3.3MHz) and velocity fields simulated using a presented pathway involving endocardial segmentation, valve position identification, and solution of the incompressible Navier-Stokes equation. Flow components defined as direct flow, delayed ejection flow, retained inflow, and residual volume were calculated by particle tracing using 4th-order Runge-Kutta integration. Additionally, systolic and diastolic average velocity fields were generated. Results indicated no major changes in average velocity fields for any of the subjects. For the two subjects with normal left ventricular function, increased direct flow, decreased delayed ejection flow, constant retained inflow, and a considerable drop in residual volume was seen at increasing stress. Contrary, for the subject with reduced left ventricular function, the delayed ejection flow increased whilst the retained inflow decreased at increasing stress levels. This feasibility study represents one of the first clinical applications of an echo-based patient-specific CFD-model at elevated stress levels, and highlights the potential of using echo-based models to capture highly transient flow events, as well as the ability of using simulation tools to study clinically complex phenomena. With larger patient studies planned for the future, and with the possibility of adding more anatomical features into the model framework, the current work demonstrates the potential of patient-specific CFD-models as a tool for quantifying 4D blood flow in the heart.

  • 235.
    Larsson, Malin
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    Caidahl, Kenneth
    Karolinska Institutet.
    Winter, Reidar
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    A new ultrasound-based approach to visualize target specific polymeric contrast agent2011In: 2011 IEEE International Ultrasonics Symposium (IUS), IEEE , 2011, 1626-1629 p.Conference paper (Refereed)
    Abstract [en]

    There are advantages of using a polymeric shelled contrast agent (CA) during ultrasound imaging instead of lipid shelled CA, e.g. particles can be attached to the surface, which enables an introduction of antibodies to the surface making the CA target specific. For this application it is essential to have a sensitive imaging technique suitable for polymeric CA. However, previously presented results have indicated difficulties in visualizing polymeric CA with commercially available contrast algorithms. Therefore a new subtraction algorithm (SA), was developed that define the difference between contrast and reference images. The aim of this study was to evaluate the response from a polymeric CA, when using the SA and compare it with existing contrast algorithms. Moreover, the possibility to detect a thin layer of CA was tested using the SA.

    Ultrasound short-axis images of a tissue-mimicking vessel phantom with a pulsating flow were obtained using a GE Vivid7 system (M12L) and a Philips iE33 system (S5-1). Repeated (n=91) contrast to tissue ratios (CTR) calculated at various mechanical index (MI) using the contrast algorithms pulse inversion (PI), power modulation (PM) and SA at a concentration of 105microbubbles/ml.

    The developed SA showed improvements in CTR compared to existing contrast algorithms. The CTRs were -0.99 dB ± 0.67 (MI 0.2), 9.46 dB ± 0.77 (MI 0.4) and 2.98 dB ± 0.60 (MI 0.8) with PI, 8.17 dB ± 1.15 (MI 0.2), 15.60 dB ± 1.29 (MI0.4) and 11.60 dB ± 0.73 (MI 0.8) with PM and 14.97 dB ± 3.97 (MI 0.2), 20.89 dB ± 3.54 (MI 0.4) and 21.93 dB ± 4.37 (MI 0.8) with the SA. In addition to this, the layer detection, when using the SA was successful.

  • 236.
    Larsson, Malin
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    Caidahl, Kenneth
    Winter, Reidar
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    A novel technique to visualize target specific polymeric contrast agents2011Conference paper (Other academic)
  • 237.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Claus, P.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    D'Hooge, J.
    Ultrasound-based 2D Strain Estimation of the Carotid Artery: an in-silico feasibility study2009In: Ultrasonics Symposium (IUS), 2009 IEEE International, IEEE , 2009, , 4 p.5441992- p.Conference paper (Refereed)
    Abstract [en]

    Ultrasound based estimation of arterial wall properties is commonly used to assess vessel wall stiffness in studies of vascular diseases. Recently, it was shown that the longitudinal motion of the vessel during systole can be measured using speckle tracking. However, the assessment of longitudinal strain in the vessel wall has to be further investigated. The aim of this study was to test the feasibility of simultaneous assessment of radial and longitudinal strain in the carotid artery using computer simulations. A kinematic cylindrical model of the carotid artery with realistic dimensions was constructed. The model was deformed radially according to temporal distention measured in-vivo while longitudinal deformation was the result of conservation of volume. Moreover, longitudinal motion was superimposed based on profiles obtained in-vivo. Ultrasound long axis images were simulated using a generalized convolution model (COLE) with realistic image properties. Four models with different scatterer distributions were built. For each of them, longitudinal and radial motion were estimated using normalized cross-correlation with spline interpolation to detect sub-sample motion. Radial and longitudinal strains, obtained by linear regression were compared with the ground truth from the model. The maximal systolic radial strain was estimated to be -12.77 ± 0.4% (ground truth -13.89%) while longitudinal strain was 5.21 ± 0.67% (ground truth 5.3%). This study shows the feasibility of simultaneously measuring radial and longitudinal strain in the carotid artery by making use of currently available hardware.

  • 238.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kremer, F.
    Claus, P.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    D'hooge, Jan
    A novel measure to express tracking quality in ultrasound block matching2010In: Proceedings - IEEE Ultrasonics Symposium, 2010, 1636-1639 p.Conference paper (Refereed)
    Abstract [en]

    Speckle de-correlation is a major problem in block matching based ultrasound methodologies as it limits the accuracy of the tracking result. It would be of benefit to have a quantitative measure expressing the local tracking quality as it would allow discarding unreliable motion estimates. We hypothesized that kernels showing sufficient gray scale pattern would more reliably track than kernels with more homogenous gray scale distributions. The aim of this study was to test this hypothesis in-silico. Ultrasound B-mode sequences were simulated from a kinematic model of the carotid artery. Two-dimensional motion was estimated using block matching with the normalized cross-correlation function as similarity measure. For each kernel, two measures of tracking quality were stored: the normalized cross-correlation coefficient (Ccc) and a measure of the amount of edges inside the kernel detected using a canny filter and counted on a pixel-by-pixel basis. As such, a quality measure (Cedge) between 0 (no edges) and 1 (nothing but edges) was obtained. Axial and lateral strains were subsequently obtained by linear regression in regions of interest (ROIs) with best/worst mean tracking quality scores. The root-mean-squared-error (RMSE) was significantly lower in regions with low Ccc (worst ROI) compared to ROIs with high Ccc. However, more edges in the kernel did indeed result in better overall tracking (lower RMSE). Thus, the proposed edge-detection method showed to be a better tracking quality measure than the commonly used Ccc.

  • 239.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Kremer, F.
    Heyde, B.
    Brodin, Lars Åke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    D'hooge, J.
    Ultrasound-based speckle tracking for 3D Strain estimation of the Arterial wall - An experimental validation study in a tissue mimicking phantom2011Conference paper (Refereed)
    Abstract [en]

    Arterial stiffness is an important risk factor for cardiovascular disease. As such, ultrasound-based methods have been proposed to assess arterial strain as a measure of stiffness. The aim of the current study was to validate our recently proposed speckle tracking (ST) algorithm to estimate the in-plane wall strain tensor in an experimental setup. Three polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties (2, 3 and 4 freeze-thaw cycles). The phantoms were connected to a pump, programmed to generate carotid flow profiles at peak flows of 7, 14, 21, 28 and 35 ml/s. Long and short-axis ultrasound images were obtained using a Vivid7 Dimension system. Radial, longitudinal and circumferential strains were estimated using the ST algorithm (kernel size: 2.7λx2λ, normalized cross-correlation; spline inter-polation for subsample motion estimation; 40% window overlap). Sonomicrometry was used to acquire reference values of strain in the phantoms. Good agreement was found between the estimated radial, longitudinal and circumferential strain and the acquired reference strain. The correlation between estimated mean peak strain values and reference peak strain values was r = 0.92 (p < 0.001) for radial strain, r = 0.72 (p = 0.006) for longitudinal strain and r = 0.91 (p < 0.001) for circumferential strain.

  • 240.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Kremer, F.
    Heyde, B.
    Widman, Erik
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    D'Hooge, J.
    Carotid strain estimation using an ultrasound-based speckle tracking algorithm2012In: 2012 IEEE International Ultrasonics Symposium (IUS), IEEE , 2012, 1394-1397 p.Conference paper (Refereed)
    Abstract [en]

    Carotid strain imaging using ultrasound-based speckle tracking has showed potential in risk stratification of cardiovascular diseases. However, assessing strain in the artery wall and in atherosclerotic plaques is challenging because of small dimensions and low deformations in relation to the applied ultrasound wavelength. High-resolution ultrasound has potential to improve the speckle tracking performance by increasing spatial resolution. The aim of this study was to compare carotid strain estimation by speckle tracking using standard clinical ultrasound and high-resolution ultrasound in an experimental setup. Ultrasound long-axis images were obtained using a standard clinical ultrasound system (Vivid7) and a high-resolution ultrasound system (Vevo2100) in dynamic phantoms mimicking the carotid artery. Speckle tracking was performed to estimate radial and longitudinal strain whereas sonomicrometry was used as reference. The results showed a significant better performance for speckle tracking applied on images from the high-resolution system compared to the standard clinical system.

  • 241.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kremer, F.
    Kuznetsova, T.
    Lind, Britta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    D'hooge, J.
    In-vivo assessment of radial and longitudinal strain in the carotid artery using speckle tracking2010In: 2010 IEEE International Ultrasonics Symposium Proceedings, IEEE , 2010, 1328-1331 p.Conference paper (Refereed)
    Abstract [en]

    Ultrasound-based algorithms are commonly used to assess mechanical properties of arterial walls in studies of arterial stiffness and atherosclerosis. Speckle tracking based techniques used for estimation of myocardial strain can be applied on vessels to estimate strain of the arterial wall. Previous elastography studies in vessels have mainly focused on radial strain measurements, whereas the longitudinal strain has been more or less ignored. However, recently we showed the feasibility of speckle tracking to assess longitudinal strain of the carotid artery in-silico. The aim of this study was to test this methodology in-vivo. Ultrasound images were obtained in seven healthy subjects with no known cardiovascular disease (39 ± 14 years old) and in seven patients with coronary artery disease (CAD), (69 ± 4 years old). Speckle tracking was performed on the envelope detected data using our previous developed algorithm. Radial and longitudinal strains were estimated throughout two cardiac cycles in a region of interest (ROI) positioned in the posterior vessel wall. The mean peak systolic radial and longitudinal strain values from the two heart cycles were compared between the groups using a student's t-test. The mean peak radial strain was -39.1 ± 15.1% for the healthy group and -20.4 ± 7.5% for the diseased group (p = 0.01), whereas the mean peak longitudinal strain was 4.8 ± 1.1% and 3.2 ± 1.6% (p = 0.05) for the healthy and diseased group, respectively. Both peak radial and longitudinal strain values were thus significantly reduced in the CAD patient group. This study shows the feasibility to estimate radial and longitudinal strain in-vivo using speckle tracking and indicates that the method can detect differences between groups of healthy and diseased (CAD) subjects.

  • 242.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Verbrugghe, Peter
    KU Leuven.
    Smoljkić, Marija
    KU Leuven.
    Heyde, Brecht
    KU Leuven.
    Famaey, Nele
    KU Leuven.
    Herijgers, Paul
    KU Leuven.
    D'hooge, Jan
    KU Leuven.
    Assessment of longitudinal strain in the Carotid artery wall using ultrasound-based Speckle tracking - validation in a sheep model2013In: Proceedings of the IEEE International Ultrasonics symposium, 2013, 2013Conference paper (Other academic)
    Abstract [en]

    Assessment of strain in the longitudinal direction of the arterial wall has been suggested to improve the evaluation of arterial stiffness and atherosclerosis. Recently, we showed the feasibility of ultrasound speckle tracking to assess carotid longitudinal strain in-silico and in-vitro. However, validation in the more challenging in-vivo setting is still lacking. The aim of this study was to validate longitudinal strain assessment in the common carotid artery (CCA) in an animal setup. The left CCAs of five sheep were exposed during Isoflurane anesthesia and sonomicrometry crystals were sutured onto the artery wall to obtain reference longitudinal strain. Ultrasound long-axis images were recorded at baseline and hypertension (Phenylephrine) and an in-house speckle tracking algorithm was applied to estimate longitudinal strain. The estimated strain curves varied cyclically throughout the cardiac cycles, showing a lengthening of the arterial segment in systole. A significant correlation between peak systolic estimated and reference strain was found (r=0.95, p < 0.001). The results indicate the feasibility of arterial longitudinal strain assessment in-vivo using ultrasound speckle tracking.

  • 243.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Computer-aided risk assessment: Claims data as expert system support for industrial safety management2001In: Safety In Action Conference: Invited paper / [ed] Safety Institute of Australia Ltd, 2001Conference paper (Refereed)
  • 244.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Decision Support for Risk Analysis in Small Enterprises2006In: 3rd International Conference Workingonsafety, 2006Conference paper (Refereed)
  • 245.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Occupational Trauma: Measurement, intervention and control1999In: Work Life 2000 Conference: Invited paper, Springer , 1999, 164-182 p.Conference paper (Refereed)
  • 246.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Pulverization of Risk - Privatization of Trauma2001Conference paper (Refereed)
  • 247.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Safety Management - Technology and health: Invited keynote lecture2004In: Health and Safety at Public Works, 2004Conference paper (Refereed)
  • 248.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Systematic Injury Prevention in Traditional Process Monitoring Work2004In: Occupational Risk Prevention / [ed] Mondelo,P, Mattila,M, Karwowski, W, Hale, A (Eds), 2004Conference paper (Refereed)
  • 249.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Systematic Safety Management: the challenge of development2002In: The 68th International conference on the prevention of occupational accidents: Invited keynote lecture, 2002Conference paper (Refereed)
  • 250.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    The logistics of distributed aged care in a local Swedish community2014Conference paper (Refereed)
    Abstract [en]

    In an attempt to map the pattern of care contacts between +65 year olds with multiple medical diagnoses living at home and their formal and informal care and service providers, 62 persons in the local council of Haninge agreed to keep a diary of all their health related contact events for a period of 6 months. The participants were visited once a fortnight and their diary inputs were recorded. The data was collected during 2011, 2012 and 2013. 20 000 contact events and 28 000 activities were recorded over 10620 participant days. Background variables like marital status, type of dwelling, type of medical problems were  related to patterns of contact with health care staff, transport services, type of care services provided, importance of family and informal care providers. The result is a fairly detailed description of the logistics requirements in a system of distributed aged care with high accessibility and retained independence.

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